Transmission and torque meter therefor



Aug. 15, 1950 v, MOORE 2,518,708

TRANSMISSION AND TORQUEMETER THEREFOR Filed Jan. 15, .1948

2 Sheehs-Sheet l v I 4O INVENTOR VINCENT MUEIRE.

5-3 BY A ATTO RNEY 2 Sheets-Sheet 2 Filed Jan. 15, 1948 INVENTOR VINCENTMUDHE. M 5. MW

ATTORNEY Patented Aug. 15, 1950 UNITED STATES AT m OFFICE TRANSMISSIONAND TORQUE METER THEREFOR Vincent Moore, Ridgewood, N. .17., assignor toWright Aeronautical *Corporation, a corporation of New York 13 Claims.

This invention relates to gear transmissions and is particularlydirected to a gear transmission including means for continuouslyindicating transmission torque and/ or to gear transmissions including aplurality of parallel connected pinions which automatically divide theload substantially equally between them.

In a gear transmission having a plurality of parallel connected pinions,it is desirable that the load be divided substantially equally betweensaid pinions. However, because of manufacturing errors-for example inthe location of the pinion bearings.it frequently happens that one ormore of the pinions tend to carry considerably more than their share ofthe load. It is an object of this invention to provide a noveltransmission, including a plurality of parallel connected pinionsrotatable about fixed axes, in which the pinions tend to automaticallydivide the load substantially equally.

A further object of the invention comprises the provision of a simpleand novel torquemeter for a transmission such that the torquemeterintroduces no radial or other lateral forces in the transmission. Inaddition the torquemeter is arranged to permit limited lateral or radialmovement of the member whose torque is being measured. With thisarrangement, when the member Whose torque is being measured comprises acarrier for a plurality of pinions, connected in parallel in thetransmission, the lateral freedom of the carrier provides for automaticequalization of the load between said pinions.

Other objects of the invention will become apparent upon reading theannexed detailed de- ,scription in connection with the drawing in which:

Figure 1 is an end View of'a transmission embodying the invention;

Figure 2 is a sectional view taken along line 2-2 of Figure 1;

Figure 3 is an enlarged sectional view taken along line 3-3 of Figure 1;

Figure l is a partial sectional view, generally similar to Figure 2, andillustrating a modifiedform of the invention; and

Figure 5 is a schematic perspective View illustrating a furthermodification of the invention.

Although the invention has been designed for use with a transmissiondisposed between an aircraft engine and its propeller, it will beobvious I however that the invention is of general application.

Referring first to Figures 1. to 3 of the drawing, as illustrated thetransmission comprises an;

input shaft it having a gear 52 formed integral therewith and an outputshaft M having an internal annular gear i6 splined to the output shaft14 at i8. When the transmission is disposed between an aircraft engineand its propeller, the shaft it is connected to said engine and theshaft The composite pinion carrier member 24, 26 is secured againstrotation by means hereinafter described. With the structure so fardescribed, the pinions 2t and gears l2 and it provide a drivingconnection from the shaft lil to the shaft I4 for driving the shaft M ata reduced speed.

The annular carrier member 24 is provided with a plurality ofsymmetrically spaced lugs 30 extending radially from the periphery ofsaid member, three such lugs being illustrated. Each of the lugs 33 hasa spherical seat 32 facing tangentially in the same rotative directionabout the axis of the carrier member 25. A bell crank lever 34 ispivotally mounted adjacent each lug 30 on a pivot pin 35 carried byspaced bosses 38 formed on a plate 5E3 secured to the engine housingstructure 42 by screws 44. One end of each bell crank lever 3i isprovided with a spherical button 45 fitted within the spherical seat 32of its associated lug 3% while the other end of said lever engages apiston 58 slidable in a cylindrical sleeve formed integral with saidplate 46. I

Each piston G8 has a reduced diameter hollow stem portion 52 fitted to acorrespondingly reduced diameter portion of the cylindrical sleeve 50thereby forming an annular cylindrical space 54 at the rear side of saidpiston.

A suitable liquid under pressure is supplied by a pump 56 to each saidannular space 54 through an annulus 58 and passages t0. each of thepistons 48 is urged outwardly from the cylinders Ell by the liquidpressure in its annular space M. Outward motion of each piston 48 islimited by a suitable stop ring 62. The stem of each piston i8 is alsoprovided with one or more drain holes or relief ports 64 communicatingwith the hollow interior of said stem which in turn communicates with adrain passage 56.

The pinion carrier member 24, 26 comprises a torque reaction member ofthe gear transmission between the shafts Ill and Hi. When the trans-Accordingly mission input shaft gear [2 is driving and rotating in aclockwise direction (Figure l) the pinion carrier member 24, issubjected to a clockwise re action torque. The arrangement is such thatclockwise motion of the carrier member 24, 28 is resisted by the pistons48 through the interposed bell crank levers 34. Accordingly the carriermember 24, 26 assumes a rotative position such that the clockwise torquereaction on the pinion carrier urges the pistons 48 against the liquidpressure acting thereon until the relief ports 54 are covered to such anextent that the torque reaction forces acting on one side of the pistonsare balanced by the liquid pressure forces acting on the other sides ofsaid pistons. Any increase in the clockwise driving torque of the shaftl8, results in a slight further closing of at least one of the reliefports 64 until said forces are again balanced. Likewise any decrease insaid torque results in a Slight opening adjustment of at least one ofthe relief ports 64 until balance is again restored between the torquereaction force on each piston and the opposing liquid pressure force.

Obviously, since the annulus space 5 behind each piston communicateswith the annulus the same liquid pressure acts on each piston andtherefore this liquid pressure is a measure of the transmission outputtorque. Accordingly a liquid pressure responsive indicating device 5 3may be connected to the annulus 58 or to any one of the annular spaces54 for measuring the transmission torque. Also it should be noted thatit is only essential for one of the piston 48 to he provided with aliquid pressure relief port 64. However, for manufacturing reasons, thepistons 58 have all been made the same.

With the aforedescribed structure, the pistons 43 resist rotation of thepinion carrier member 24;, is in a clockwise direction (Figure 1) andthe li uid pressure acting on said pistons is a measure of the clockwisetorque acting on said membeer, The carrier member M is also providedwith axially extending lugs Til adapted to engage shoulders '52 on theplates 48 to prevent rotation of said carrier member in the reverse orcounterclockwise direction.

As stated, the same liquid pressure acts on each piston 48 and thereforethe same tangential force is exerted on each lug r ll on the pinioncarrier member 24, 26. In addition said lugs are symmetrically disposedabout the axis Of said gear member. Therefore, the torque measuringforces subject the carrier member 24, 2% to only pure torque.

The pivot pin 36 of each bell crank lever Ltd :is substantially radiallydisposed. In addition each said lever is provided with some clearance Hibetween it and its associated pivot pin supporting bosses 33 therebypermitting limited movement-of each bell crank lever 34 along its pivotpin 35. With this arrangement the pinion carrier member M, 26 is free toshift radially or laterally a limited extent relative to the axes of itsinput gear l2 and the axes of its output gear [6.

Since the tangential reaction forces acting on the lugs Bi of the pinioncarrier member 24 subjects said member only to pure torque, the bellcrank levers 3 provide no radial restraint to the position of saidpinion carrier member, Within the limits of movement of said leversbetween their pivot pin supporting bosses 33, except for the smallfrictional restrainttomcvement of said levers along their respectivepivot pins 35. ,Ac-

cordingly the pinion carriermembcrfis 1 fl ats between the gears I2 andI6 whereby if one of the pinions 263 tends to assume more than its shareof the load, the pinion carrier member will shift laterally until theload is substantially equally divided between all the pinions.

As illustrated, the two arms of each bell crank lever 34 are'of unequallength such that the range of motion of the carrier member lugs 39 issubstantially less than that of the pistons 48. With this arrangement,the motion of the carrier member about the transmission axis can be keptquite small and still provide ample movement of the pistons 48 forcontrolling the liquid pressure acting thereon. In an actualinstallation, the range of movement of the pistons 48, between no loadand full load'torque, is of the order of a small fraction of an inch, sothat the carrier member 2 5, 26 has no appreciable motion about thetransmission axis.

With the pivot pins 36 disposed radially, the inter-locking engagementof the spherical buttons 46 with the spherical seats 32 locates thecarrier member 24, 26 axially in spite of the freedom of movement ofeach bell crank lever along its pivot pin 36. The small pivotal movementof the bell crank levers 34 between no load and full load torque has noappreciable affect on the axial position of the pinion carrier member24, 26 because the bell crank lever arms, engaging the spherical seats32, are disposed substantially at right angles to the path of motion oftheir respective seats 32. Also, as a result of the radial dispositionof the pivot pins 36, the axes of the pistons 48 are spaced from and aredisposed parallel to the axisiof the transmission. Accordingly saidpistons can be conveniently disposed about either the input shaft IE! orthe output shaft I4 of the transmission, thereby providing a verycompact arrangement.

In order to provide lubrication of the bearing surfaces of the pinions2%, the carrier member 25 is provided with passages each communieatingat one end with the bearing surfaces of one of said pinions and at itsother end with an internal annular groove 82 on the hub portion of saidcarrier member. An oil transfer bushing 35 is disposed between said hubportion and the hollow shaft M. The oil transfer bushing 85 is providedwith radial holes 88 communicating at one end with said annular groove32 and at their other ends with an internal annular groove fill in saidbushing. The shaft It is also provided with radial holes 92communicating with the annular groove 98 in said bushing. With thisarrangement, lubricating oil is supplied to the bearing surfaces of thepinions 2!! from the interior of the shaft ill via holes annular groove9! holes 38, annular groove and passages 8G.

The provision of the oil transfer bushing 85 limits the range of freefloating movement of the pinion carrier member 2 3, 25 relative to theinternal gear [6, to the thickness of the oil film between said bushingand the shaft Hi. In general, however, a larger range of radial floatingmovement of the pinion carrier is preferable, as is provided by the oiltransfer sleeve construction of Figure l.

ure 2) has an annular side plate I06 secured thereto at its hub byscrews IIJI to form an annular groove I08 within which an annular flangeIII] on the oil transfer sleeve I is received. The sleeve I!!!) isprovided with radial passages H2 to which oil is supplied from theinterior of the shaft-like member IllI through the oil transfer bushingI92 in much the same manner that oil is supplied to the passages 80 ofFigure 2. From the sleeve passages II2, the oil enters the annulus I08from which it is supplied to the bearing surfaces ofv the pinions 20through passages II4 in the pinion carrier member I04. The oil transfersleeve I00 and pinion carrier member I34 are locked against relativerotation by interfitted tabs H3 and H8. In addition an angular springI20, secured to the plate I05, urges the flange III] against one side ofthe channel IE8 to prevent leakage of lubricating oil therebetween andat the same time the spring I20, by reason of its annular construction,prevents leakage of lubricating oil between the outer side of thechannel I98 and the flange HQ. The annular telescopic fit between thepinion carrier member m4 and the oil transfer sleeve flange H3 comprisesa flexible connection therebetween permitting said. carrier member tomove radially and laterally relative to the shaft-like member IEI andthe transmission gears without disturbing the transfer of lubricatingoil from said shaft-like member to the pinion carrier member I84.

In Figure 4, the pinions are lubricated by oil supplied to their carriermember I34 from the shaft-like member IEBI. Like the shaft I4 of Figures1-3, the member I il may comprise the output shaft of the transmissionor it may comprise a stationary member. Except for its small radial orlateral floating movement and its small rotary movements, the pinioncarrier member 26 or I34 is stationary so that oil may readily besupplied thereto from any stationary member by a flexible connectionpermitting said small relative movements, as for example by a flexibleconduit.

In the structure so far described, the torquemeter indicates the engineoutput torque only when the torque reaction on the pinion carrier memberis in one rotative direction (clockwise in Figure l) When the directionof this reaction torque reverses, it is resisted by the engagement ofthe flange or flanges I6 with the stopshoulder or shoulders I2 so thatthere is no measurement of the magnitude of this reverse torque.However, in the case of an aircraft engine drivably connected to abladed propeller for providing the aircraft with forward thrust, it iscommon practice to also use the propeller for providing reverse thrustin order to brake the forward motion of the aircraft. Accordingly incertain aircraft instaliations, it may be desirable-for example forcontrol purposes-to measure the torque during reverse thrust operationof the aircraft propeller as well as during its forward thrustoperation. Figure diagrammatically illustrates a novel arrangement forthis purpose.

In Figure 5, a pinion carrier member I33 for a gear transmission, isschematically indicated in the dot and dash outline, said transmissionbeing similar to that of Figures l4. The carrier member I38 is providedwith an even number of symmetrically spaced lugs I32 extending radiallyoutwardly from its periphery, four such lugs b ing indicated on thedrawing. The structure of the carrier member I30, except for thestructure 1' of its lugs I32, may be similar to the carrier member 24,26 of Figures 1 to 4. An even number of pistons I34, equal to the numberof lugs I32, are symmetrically disposed about the axis of the carriermember I30, midway between the lugs I32, each piston being slidable in afixed cylinder I35. In addition a plurality of levers I36 are provided,each of said levers being pivotally mounted about a pivot pin I38disposed radially relative to the axis of the carrier member I38 andadjacent one of the lugs I32. Each said lever I36 is provided with aforked extension I4ll straddling its adjacent lug I32 and one arm I42 ofeach lever is adapted to engage one of the adjacent pistons I34 and theother arm I44 of each lever is adapted to engage the other adjacentpiston, the arms I42 and I 44 being of equal length. A suitable liquidunder pressure is supplied by a pump I45 to the rear side of each pistonI34 through a conduit I48 and a passage I49 extending through the rearWall of each cylinder I35. The magnitude of this pressure is controlledby one or more drain holes I53, each controlled by a piston I34.

With this arrangement of Figure 5, clockwise torque acting on the pinioncarrier member I3II is resisted through engagement of the lever arms I44with the pistons I34. Similarly counterclockwise torque acting on thecarrier member I30 is resisted through engagement of the lever arms I42with the pistons I34. In each case, the pistons I34 assume a position inwhich the liquid pressure acting thereon balances the torque reaction onthe carrier membe I30. Accordingly the liquid pressure acting on thepistons I34 is a measure of the reaction torque on the pinion carriermember I 30 regardless of the direction of said torque. A pressureresponsive indicating device I52 is connected to the conduits I48 toindicate the magnitude of the reaction torque acting on the pinioncarrier member I30, which torque is proportional to the output torque ofthe transmission.

In Figure 5, the levers I36 are only schematically illustrated. However,said levers are preferably slidable along the axes of their respectivepivot pins I38 and each side of their forked ends I40 preferably has aspherical connection with a pinion carrier member lug I 32 similar tothat provided by each spherical button 46 and its socket 32 of Figures 1to 3.

While I have described my invention in detail in its present preferredembodiments, it will be obvious to those skilled in the art, afterunderstanding my invention, that various changes and modifications maybe made therein without departing from the spirit or scope thereof. Iaim in the appended claims to cover all such modifications.

I claim as my invention:

1. In combination with a transmission comprising an input member, anoutput member, and a reaction member: a plurality of pistonssymmetrically spaced about the axis of said reaction member; a pluralityofsupport members each having a cylindrical bore within which one ofsaid pistons is slidable; means for supplying liquid under pressure tosaid cylindrical bores for application against their respective pistons;a lever interconnecting each piston with said, reaction member such thattorque on said reaction member is resisted by the liquid pressureapplied against said pistons; each of said levers being pivotallymounted on one of said supportv members.

amazes 2 -.,In atransmission: a first gear; a: second gear concentricwith. said first gear; av carrier member concentric with said gears;a'plurality' of pinions mounted on said carrier member and disposed inmeshing engagement with said-gears for providing a driving connectiontherebetween; means for providing a supply of oil; afiexible connectionbetween said means and said carrier mem:- her for supplying oil to saidcarrier member while permitting radial movement of said carrier member.relative to said gears.

3; In atransmission: a first gear; axsecond gear concentric-with saidfirst gear; a'carrier member concentric with said gears; a plurality ofpinions mounted on said carrier member and disposed in, meshing.engagement with said gears for providing. a driving connectiontherebetween; an annular member; said annular member andcarrier havingpassages for supplying lubricating oilfrom said annular member throughsaid pas sages to bearing surfaces of said pinions, said annular memberand said carrier member also having annular telescopic portionspermitting relative radial movement between said members withoutinterrupting. the supply of lubricating oil to saidpinion bearingsurfaces.

4. In a. transmission: a first gear; a. second gear concentric with saidfirst gear; a carrier member concentric withsaid gears; a plurality ofpinions mounted on. said carrier member and disposed in meshing.engagement with said gears for providing a driving connectiontherebetween; an annular member; said annular member and carrier memberhaving passages for supplying lubricating oil from said. annular memberthrough said passages to bearing surfaces of said pinions; said annularmember and said carrier member also having annular telescopic. portionspermitting relative radial movement between said members withoutinterrupting the supply of.lubricating. oil to said pinion bearingsurfaces; a plurality of pistons symmetrically spaced about the axis ofsaid carrier member; means forsupplying liquid under pressureagainstsaid pistons; and means operatively interconnecting said. reactionmemberand pistons so that reaction member torque is resisted by liquidpressure on said pistons.

5. A transmission as described in claim 4-ineluding valve port meanscontrolled by at least one of said pistons for regulating said liquidpressure.

6. A. transmission as recited in. claim 4. in which the connectionbetween each saidpiston and said reaction member comprises a leverhaving its ends respectively abutting said piston and reaction member,each said lever being mounted for pivotal movement about an axisdisposed subtantially radial relative to the axis of said reactionmember and being mounted for limited movement along its pivot axis.

7. In combination with a transmission comprising an input member, anoutput member and a torque reaction member: a plurality of pistons;

a plurality of levers operatively connecting said -8.- A: transmissioncomprising an input mem.- ber; an output member; a reaction member; anannular gear on oneof said members; an annular gear; on another of saidmembers concentric with said first-mentioned gear; a pluralityof pinionson the remaining one of said members meshing with said annular gears; aplurality of pistons symmetrically spaced about the axis of said.reaction member; means for supplyinga fluid under equal pressure againstsaid pistons; and means-operatively connecting said reaction member tosaid pistons so that reaction member torque is resisted by the fluidpressure acting against said pistons, the connection between each saidpiston and said reaction member comprising arleverzhaving-its endsrespectively abuttingsaid piston and reaction member, the pivot axes ofsaid levers being disposed substantially radial relative to the axis ofsaid reaction member and the piston axes being disposed parallel to butspaced from the reaction member axis.

9. A transmission comprising an input member; an output member; areaction member; an annular gear on one of said'members; an-annular gearon another of said members concentric with said first-mentioned gear; aplurality of pinions onthe remaining one of said members meshing withsaid annular gears; a plurality of pistons symmetrically spaced aboutthe axis. of said reaction member; means for supplying a fluid underequal pressure against said pistons; and means operatively connectingsaid reaction member to said pistons 50 that reaction member torque isresisted by the fluid pressure acting against said pistons, theconnection between each said piston and said reaction member includin alever which is yieldable radially relative to the axis of said reactionmember.

10. A transmission as recited in claim 9 in which the connection betweeneach said piston and said carrier member comprises a lever having itsends respectively abutting said piston and carrier member, each saidlever being mounted for'pivotal movement about an axis disposed substantially radial relative to the axis of said reaction member and beingmounted for limited movement along its pivot axis.

11. A transmission comprising a first gear; a second gear concentricwith said first gear; a carrier member concentric with said gears; aplurality of pinions mounted on said carrier member and disposed inmeshing engagement with said gear for providing a driving connectiontherebetween; a plurality of pistons substantially symmetrically spacedabout the axis of said gears, means for supplying a fluid under equalpressure against said pistons; and means operatively connecting saidcarrier member to said pistons so that the torque reaction on saidcarrier member, resulting from transmission of torque from aid firstgear to said second gear, is resisted by the fluid pressure acting onsaid pistons, the connection between each said piston and said carriermember comprising a lever having its ends respectively abutting saidpiston and carrier memher, the pivot axes of said levers being disposedsubstantially radial relative to the axis of said carrier member and thepiston axes being disposed parallel to but spaced from the reactionmember axis.

12. A transmission comprising a first gear; a second gear concentricwith said first gear; a carrier member concentric with said gears; aplurality of pinions mounted on said carrier member and disposed inmeshing engagement with said gear for providing a driving connectiontherebetween; a plurality of pistons substantially symmetrically spacedabout the axis of said gears, means for supplying a fluid under equalpressure against said pistons; and means operatively connecting saidcarrier member to said pistons so that the torque reaction on saidcarrier member, resulting from transmission of torque from said firstgear to said second gear, is resisted by the fluid pressure acting onsaid pistons,.the connection between each said piston and said carriermember comprisingifa lever which is yieldable radially relative to theaxis of said carrier member.

13. A transmission comprising an input memher; an output member; areaction member; an annular gear on one of said members; an annular gearon another of said members concentric with said first-mentioned gear; aplurality of pinions on the remaining one of said members meshing withsaid annular gears; a plurality of pistons symmetrically spaced aboutthe axis of said reaction member; means for supplying a fluid underpressure against said pistons; and means operatively connecting saidreaction-memher to said pistons so that reaction member torque isresisted by the fluid pressure acting REFERENCES CITED The followingreferences are of record in the file of this patent? UNITED STATESPATENTS Number Name Date 505,396 Esmond Sept. 19, 1893 1,864,348 GivenJune 21, 1932 2,154,489 Buck Apr. 18, 1939 2,182,789 Cotanch Dec. 12,1939 2,225,863 Halford et a1 ..Dec. 24, 1940 2,231,784 Van Thungen Feb.11, 1941 2,346,168 Jones Apr. 11, 1944 2,386,367 Taylor Oct. 9, 19452,444,363 Newcomb June 29, 1948

